When you tire of rummaging through San Telmo's designer racks and museums, head over to El Zanjón de Granados for insight into Buenos Aires' far-stretching, 500-year history. From the outside, the building looks like an immense, lavish mansion. But beneath this glamorous structure, you'll catch a glimpse of Buenos Aires' past as you traverse a maze of ancient Spanish settlements.

Tour guides relay enchanting tales of the city's history as you descend into through El Zanjón's network of underground tunnels. You'll admire ancient artifacts, old walls, and flooring and decide what to believe for yourself. One TripAdvisor describes a visit here as a "fascinating look at the past."

Zanjón de Granados is located in San Telmo and is easily accessible via the Independencia subte stop. Guided tours in Spanish and English are offered every hour Monday through Friday from 11 a.m. to 3 p.m. and every 20 minutes on Sundays between 1 and 6 p.m. Tours last between 30 minutes and two hours. For further details, consult the official website.